U.S. patent application number 10/848270 was filed with the patent office on 2005-06-23 for elastically distensible folding member.
Invention is credited to Kelley, Gregory S., Vigil, Dennis M..
Application Number | 20050137617 10/848270 |
Document ID | / |
Family ID | 46302076 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050137617 |
Kind Code |
A1 |
Kelley, Gregory S. ; et
al. |
June 23, 2005 |
Elastically distensible folding member
Abstract
An elastically distensible folding member is disclosed. The
folding member can be formed with a wall that is substantially
shaped as a tube when the folding member is in a relaxed (i.e.
unstressed) state. The tubular shaped folding member defines a tube
axis and can have an axially aligned slit that extends through the
wall. The folding member can be used to cover an incising element
that is attached to the balloon and positioned in the lumen of the
tubular folding member. During balloon inflation, the folding
member can be deformed to expose the tip of the incising element to
allow for a tissue incision.
Inventors: |
Kelley, Gregory S.; (San
Diego, CA) ; Vigil, Dennis M.; (San Diego,
CA) |
Correspondence
Address: |
NEIL K. NYDEGGER
NYDEGGER & ASSOCIATES
348 Olive Street
San Diego
CA
92103
US
|
Family ID: |
46302076 |
Appl. No.: |
10/848270 |
Filed: |
May 18, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10848270 |
May 18, 2004 |
|
|
|
10742166 |
Dec 19, 2003 |
|
|
|
Current U.S.
Class: |
606/170 ;
604/103.14; 606/194 |
Current CPC
Class: |
A61B 2017/22061
20130101; A61B 2090/08021 20160201; A61B 17/320725 20130101 |
Class at
Publication: |
606/170 ;
606/194; 604/103.14 |
International
Class: |
A61B 017/32 |
Claims
What is claimed is:
1. An incising device for use on a medical catheter to incise
biological material at a treatment site, said incising device
comprising: a balloon defining a balloon axis, said balloon being
inflatable from a first deflated configuration to a second radially
expanded configuration; an elongated incising element having an
incising tip and mounted on said balloon to extend radially
therefrom when said balloon is in said radially expanded
configuration; and an elastic folding member having a substantially
tubular shape when said folding member is in a relaxed state, said
folding member being bonded to said outer surface of said balloon
and sized to cover said tip when said balloon is deflated, said
folding member being oriented on said balloon and formed with an
axially aligned slit, with said folding member deforming in
response to a balloon inflation to expose said incising tip for
incision of the biological material.
2. An incising device as recited in claim 1 wherein said incising
element is a cutting blade and said incising tip is a cutting
edge.
3. An incising device as recited in claim 2 wherein said cutting
blade is elongated and oriented on said balloon longitudinally.
4. An incising device as recited in claim 2 wherein a portion of
said cutting blade is embedded in said folding member.
5. An incising device as recited in claim 1 wherein said incising
element is an injector.
6. An incising device as recited in claim 1 wherein said folding
member extends from a first axially aligned edge to a second
axially aligned edge and said incising element is positioned midway
between said edges.
7. An incising device as recited in claim 1 wherein said folding
member extends from a first axially aligned edge to a second
axially aligned edge and said incising element is positioned closer
to said first edge than said second edge to overlap said first and
second edges when said balloon is in said deflated
configuration.
8. An incising device for use on a medical catheter to incise
biological material at a treatment site, said device comprising: an
elongated balloon having an outer surface and defining a
longitudinal balloon axis, said balloon being inflatable from a
first deflated configuration to a second radially expanded
configuration; an incising element having an incising tip and
mounted on said outer surface of said balloon; and an elastic
folding member mounted on said outer surface of said balloon and
having a wall that is substantially tubular shaped when said
balloon is in said deflated configuration, said folding member
formed with an axially aligned slit that extends through said wall
to establish first and second axially aligned edges with said first
edge being substantially juxtaposed with said second edge when said
balloon is in the deflated configuration, and wherein said folding
member is oriented on said balloon with said tube axis
substantially parallel to said balloon axis.
9. An incising device as recited in claim 8 wherein said incising
element is a cutting blade and said incising tip is a cutting
edge.
10. An incising device as recited in claim 9 wherein said cutting
blade is elongated and oriented on said balloon longitudinally.
11. An incising device as recited in claim 9 wherein a portion of
said cutting blade is embedded in said folding member.
12. An incising device as recited in claim 8 wherein said incising
element comprises an injector.
13. An incising device as recited in claim 8 wherein said incising
element is positioned midway between said first and second
edges.
14. An incising device as recited in claim 8 wherein said incising
element is positioned closer to said first edge than said second
edge to overlap said first and second edges when said balloon is in
said deflated configuration.
15. A catheter comprising: a catheter tube; an elongated inflatable
balloon mounted on said catheter tube, said balloon having an outer
surface and defining a balloon axis in the direction of balloon
elongation; and an elastic folding member having a wall that is
substantially tubular shaped in a relaxed state, said tube defining
a tube axis and having a pair of edges, said edges being
substantially juxtaposed when said folding member is in the relaxed
state; said folding member being bonded on said outer surface of
said balloon with said tube axis substantially parallel to said
balloon axis.
16. A catheter as recited in claim 15 wherein said tube shaped wall
establishes a tube lumen and said catheter further comprises an
incising element having an incising tip and mounted on said balloon
and extending therefrom with said incising tip positioned in said
tube lumen when said folding member is in the relaxed state to
protect said incising tip during transit to a treatment site.
17. A catheter as recited in claim 16 wherein said incising element
is a cutting blade and said incising tip is a cutting edge.
18. A catheter as recited in claim 17 wherein said catheter tube
defines a longitudinal axis, said cutting blade is elongated, and
said cutting blade is oriented on said balloon substantially
parallel to said longitudinal axis.
19. A catheter as recited in claim 17 wherein at least a portion of
said cutting blade is embedded in said folding member.
20. A catheter as recited in claim 16 wherein said incising element
is an injector.
Description
[0001] This application is a continuation-in-part of application
Ser. No. 10/742,166, filed Dec. 19, 2003, which is currently
pending. The contents of application Ser. No. 10/742,166 are
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention pertains generally to medical devices.
Some embodiments of the present invention pertain to catheters for
the revascularization of coronary and peripheral vessels. The
present invention is particularly, but not exclusively, useful as
an incising balloon having sharp incising elements, such as
atherotome blades or injectors, that are shielded when the balloon
is deflated.
BACKGROUND OF THE INVENTION
[0003] Arterial blockages caused by the build up of plaque in the
arteries of a patient can have grave consequences. Specifically,
the build up of plaque in arteries can reduce and eventually block
the flow of blood through the affected vessel. When blood flow is
reduced in the coronary arteries, the heart muscle can become
deprived of oxygen, and the patient is often prone to suffer
angina. In severe cases of coronary artery blockage, the patient
can suffer a heart attack.
[0004] Fortunately, many modern surgical techniques, such as
percutaneous transluminal coronary angioplasty (PTCA), have been
developed to alleviate the stenoses that are formed when plaque
builds up in a patient's arteries. These procedures use a balloon
angioplasty device to relieve arterial stenoses by compression of
the stenosis. In angioplasty surgery, the balloon of a balloon
catheter is initially attached to a catheter tube in a deflated
configuration. The balloon is then inserted into and advanced
through the vasculature of the patient until the balloon is
positioned across the stenosis requiring treatment. Once the
balloon has been properly positioned, fluid is infused into the
balloon. As the balloon expands, it dilates the lumen of the artery
and compresses the plaque. The balloon is subsequently deflated
and, once in its deflated configuration, it is either withdrawn
from the artery or placed across another stenosis, to restore
normal blood flow through the artery.
[0005] A particular problem associated with an angioplasty
procedure exists during the deflation stage of the balloon, prior
to its removal from the artery. In greater detail, it is desirable
that the balloon be deflated as tightly as practicable to
facilitate its removal from the arterial passageways. Specifically,
it is desirable to have the balloon collapse evenly and compactly
during balloon deflation. Once deflated, the balloon catheter must
often travel through tortuous passageways and it is, therefore,
desirable to have the balloon deflate uniformly into a predictable
configuration. If the balloon fails to deflate in a uniform manner,
an irregular bulge in the balloon may cause difficulties in
withdrawing the balloon catheter from the artery.
[0006] Although conventional percutaneous transluminal coronary
angioplasty (PTCA) procedures have been somewhat effective in
treating coronary artery disease, cutting balloons can also be an
effective treatment option for the revascularization of both
coronary and peripheral vessels. The cutting balloon mechanism is
unique in that the balloon pressure is distributed over one or more
blades (i.e. microtomes). The blade(s) function as stress
concentrators and cut initiators in PTCA atherectomy procedures. In
some cases, PTCA atherectomy procedures may be effective in
reducing vessel recoil and vessel injury and in lowering the rate
of restenosis, as compared to conventional PTCA procedures.
[0007] The atherotome blades used in cutting balloons are extremely
sharp (e.g. three to five times sharper than a conventional
scalpel). It is desirable that the blades do not tear, cut or
perforate the inflation balloon during assembly of the cutting
balloon, handling or during clinical use. In addition to balloon
perforation concerns, an inadvertent incising of tissue as the
cutting balloon is being moved through the vasculature is also
undesirable.
[0008] Along these lines, a device having a blade-like structure
which is described as a "parting edge" which is shielded within the
pleats of an expandable clover leaf shaped tube is disclosed by
Shiber in U.S. Patent Application Publication No. 2002/0151924,
filed Oct. 17, 2002 and entitled "Clover Leaf Shaped Tubular
Medical Device". However, the clover leaf design disclosed by
Shiber does not necessarily protect the relatively fragile balloon
from the "parting edges." This is because the "parting edges" are
located within the pleats of the balloon leaving portions of the
balloon exposed to the "parting edges" when the device is twisted,
turned and bent through the curved vasculature of a patient.
[0009] In addition to the conventional PTCA treatments and PTCA
atherectomy procedures described above, it is sometimes desirable
to inject a medicament into a vessel wall. For example, U.S. Pat.
No. 6,102,904 which issued to Vigil et al. on Aug. 15, 2000 for an
invention entitled "Device for Injecting Fluid into a Wall of a
Blood Vessel," and which is assigned to the same assignee as the
present invention, discloses such a device. As disclosed in Vigil
'904, the device includes an inflatable balloon that is mounted on
a catheter and a plurality of injectors that extend outwardly from
the balloon. A fluid passageway is provided to place each injector
in fluid communication with a fluid source. During use of the
device, the balloon is first positioned in a vessel proximate the
treatment area. Next, the balloon is inflated to embed the
injectors into the vessel wall. Subsequently, fluid from the fluid
source is introduced into the fluid passageway and through the
dispensers into the treatment area. Like the atherotome blades
described above, it is desirable that the injectors do not tear,
cut or perforate the inflation balloon during assembly of the
cutting balloon, handling or during clinical use.
[0010] In light of the above, the present invention is directed to
unique devices and methods for refolding the balloon of a balloon
catheter. In addition, the present invention is directed to balloon
refolding devices and corresponding methods of use which are
relatively simple to implement and comparatively cost
effective.
SUMMARY OF THE INVENTION
[0011] The present invention is directed to an elastically
distensible folding member for use on the balloon of a balloon
catheter. In one application of the present invention, the folding
member can be used to refold a dilatation balloon during a balloon
deflation to facilitate movement of the balloon through a body
vessel. In another application, the folding member is used as a
sheath to cover an incising element that is attached to an
inflatable balloon during movement of the balloon through a body
vessel. For example, the folding member can be used to protect an
incising element such as a cutting blade, injector or round wire
when the balloon is deflated and thereafter expose the incising
element during a balloon inflation to incise target tissue at a
treatment site in a body vessel of a patient. In a particular
embodiment, the folding member can be used to protect the tip of an
injector when the balloon is deflated and thereafter expose the
injector tip during a balloon inflation to allow a medicament to be
dispensed into a target tissue.
[0012] For use with the present invention, the catheter typically
includes an elongated, inflatable balloon that defines a balloon
axis in the direction of elongation. When deflated, the balloon can
be somewhat easily passed through bodily conduits, such as a
patient's vasculature, allowing the balloon to be advanced to and
withdrawn from a treatment site. Once the balloon has been
positioned at the treatment site, the balloon can be inflated into
a radially expanded configuration. This balloon expansion can be
used to dilate a vessel lumen, drive an incising element into a
target tissue, or both.
[0013] In accordance with the present invention, each folding
member is made of an elastic material and is formed with a wall
that is substantially shaped as an elongated tube when the folding
member is in a relaxed (i.e. unstressed) state. The tubular shaped
folding member defines a tube axis in the direction of elongation
and is formed with an axially aligned slit that extends radially
through the wall. For the folding member, the slit establishes a
pair of axially aligned edges that are substantially juxtaposed
when the folding member is in the relaxed state.
[0014] One or more folding member(s) can be bonded to the outer
surface of the inflatable balloon and oriented to align each tube
axis substantially parallel with the balloon axis. With this
cooperation of structure, the folding member is tubular shaped
while the balloon is deflated and is elastically deformed during a
balloon inflation. Specifically, during a balloon inflation, the
folding member deforms from its tubular shape with the edges
separating from their initial juxtaposed configuration. When the
balloon is fully inflated, at least a portion of the folding member
substantially conforms with the outer surface of the balloon which
is typically cylindrical shaped at full inflation. After the tissue
has been dilated, the balloon can be deflated, a process in which
the folding member returns to its relaxed, tubular shape.
[0015] In one aspect of the present invention, the folding member
can be used to cover a rigid, incising element that is mounted on
the outer surface of the balloon. Specifically, for the present
invention, each incising element has an incising tip and extends
from the outer surface of the balloon to the incising tip. For
example, the incising element can be a cutting blade that extends
to a cutting edge or an injector that extends to an injector tip.
For these embodiments, the tubular folding member is bonded to the
outer surface of the balloon with the tip of the incising element
positioned in the lumen of the tubular folding member (when the
folding member is tubular shaped and in the relaxed state). With
this cooperation of structure, the folding member covers the tip of
the incising element when the balloon is deflated (and the folding
member is relaxed).
[0016] When the balloon is inflated, the balloon can become taut
and elastically deform the folding member. As a consequence, the
folding member deforms from its initial, relaxed shape during
balloon inflation and the edges separate from their initial
juxtaposed configuration. Eventually, with continued balloon
inflation, the folding member deforms until the tip of the incising
element becomes exposed. Once exposed, the tip of the incising
element can be driven into the target tissue. In a particular
embodiment, the folding member can be used to protect the tip of an
injector when the balloon is deflated and thereafter expose the
injector tip during a balloon inflation to allow a medicament to be
dispensed into a target tissue.
[0017] After the tissue has been incised (and in some cases
injected with medicament), the balloon can be deflated, a process
in which the folding member returns to its relaxed shape. During a
balloon deflation, the folding member folds the balloon and, once
relaxed, the folding member covers the tip of the incising element
to prevent the inadvertent cutting of tissue and balloon
perforation during withdrawal of the catheter from the treatment
site.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The novel features of this invention, as well as the
invention itself, both as to its structure and its operation, will
be best understood from the accompanying drawings, taken in
conjunction with the accompanying description, in which similar
reference characters refer to similar parts, and in which:
[0019] FIG. 1 is a simplified, perspective view of a catheter
having an incising device operationally positioned in the upper
body of a patient;
[0020] FIG. 2 is an enlarged, perspective view of an incising
device, shown with the balloon inflated;
[0021] FIG. 3 is a cross-sectional view of the incising device
shown in FIG. 2 as seen along line 3-3 in FIG. 2;
[0022] FIG. 4 is a cross-sectional view as would be seen along line
3-3 in FIG. 2 showing the incising device after the balloon has
been deflated;
[0023] FIG. 5 is a cross-sectional view as would be seen along line
3-3 in FIG. 2 showing a portion of an alternate embodiment of an
incising device in which the incising element is positioned closer
to one axially aligned edge of the folding member than the other
axially aligned edge of the folding member, shown with the balloon
in the inflated state;
[0024] FIG. 6 is a cross-sectional view as would be seen along line
3-3 in FIG. 2 of the embodiment shown in FIG. 5, shown with the
balloon in the deflated state;
[0025] FIG. 7 is a cross-sectional view as would be seen along line
3-3 in FIG. 2 showing an embodiment of an incising device in which
the incising element is an injector for injecting a medicament into
selected tissue at a treatment site, shown with the balloon in the
inflated state;
[0026] FIG. 8 is a cross-sectional view as would be seen along line
3-3 in FIG. 2 of the embodiment shown in FIG. 7, shown with the
balloon in the deflated state;
[0027] FIG. 9 is a cross-sectional view as would be seen along line
3-3 in FIG. 2 showing another embodiment of a refolding device for
an angioplasty balloon, shown with the balloon in the deflated
state; and
[0028] FIG. 10 is a cross-sectional view as would be seen along
line 3-3 in FIG. 2 of the embodiment shown in FIG. 9, shown with
the balloon in the inflated state.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Referring initially to FIG. 1, a catheter 20 having an
incising device 22 is shown for performing a medical procedure at
an internal treatment site of a patient 24. More specifically, the
catheter 20 is shown positioned to treat a lesion in an upper body
artery of a human patient. Although the catheter 20 is capable of
performing a medical procedure in an upper body artery such as a
coronary artery, those skilled in the pertinent art will quickly
recognize that the use of the catheter 20 as herein described is
not limited to use in a specific artery, but, instead can be used
in vascular conduits and other ductal systems (e.g. a bile duct or
urinary tract) throughout the human body. Moreover, although FIG. 1
shows the catheter 20 used in a human body, it is to be appreciated
that the catheter 20 can also be used in non-humans (e.g. animals)
if desired. Functionally, the catheter 20 is configured to incise a
biological material from within a body conduit. As used herein, the
term "biological material" and its derivatives includes, but is not
limited to, cellular matter including tissue (diseased, healthy or
otherwise), deposits such as cholesterol and calcium deposits, and
lesions which, for example, may consist of cellular matter and/or
deposits.
[0030] Referring now to FIG. 2, it can be seen that the incising
device 22 is attached to the distal end 26 of a catheter tube 28.
FIG. 2 further shows that the incising device 22 can include an
inflatable balloon 30 that typically includes a cylindrical shaped
working section 32 that defines an axis 33.
[0031] For the catheter 20, the inflatable balloon 30 can be made
of a compliant, semi-compliant or non-compliant material.
Specifically, any suitable thermoplastic or thermosetting material
may be used in accordance herewith including both elastomeric and
non-elastomeric materials. Thermoplastic materials find particular
utility herein. Examples of non-elastomeric materials include, but
are not limited to, polyolefins including polyethylene and
polypropylene, polyesters, polyethers, polyamides, polyurethanes,
polyimides, and so forth, as well as copolymers and terpolymers
thereof. As used herein, the term "copolymer" shall hereinafter be
used to refer to any polymer formed from two or more monomers.
[0032] Examples of suitable elastomeric materials include, but are
not limited to, elastomeric block copolymers including the styrenic
block copolymers such as styrene-ethylene/butylene-styrene (SEBS)
block copolymers disclosed in U.S. Pat. No. 5,112,900 which is
incorporated by reference herein in its entirety. Other suitable
block copolymer elastomers include, but are not limited to,
styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS),
styrene-isobutylene-styrene (SIBS) and so forth. Block copolymer
elastomers are also described in commonly assigned U.S. Pat. Nos.
6,406,457, 6,171,278, 6,146,356, 5,951,941, 5,830,182 and
5,556,383, each of which is incorporated by reference herein in its
entirety.
[0033] Elastomeric polyesters and copolyesters may be employed
herein. Examples of elastomeric copolyesters include, but are not
limited to, poly(ester-block-ether) elastomers,
poly(ester-block-ester) elastomers and so forth.
Poly(ester-block-ether) elastomers are available under the trade
name of HYTREL.RTM. from DuPont de Nemours & Co. and consist of
hard segments of polybutylene terephthalate and soft segments based
on long chain polyether glycols. These polymers are also available
from DSM Engineering Plastics under the trade name of
ARNITEL.RTM..
[0034] Non-elastomeric polyesters and copolymers thereof may be
employed, such as the polyalkylene naphthalates, including
polyethylene terephthalate and polybutylene terephthalate, for
example. Polyamides including nylon, and copolymers thereof, such
as poly (ether-block-amides) available under the trade name of
PEBAX.RTM. from Atofina Chemicals in Philadelphia, Pa., are
suitable for use herein. Suitable balloon materials are described
in commonly assigned U.S. Pat. Nos. 5,549,552, 5,447,497,
5,348,538, 5,550,180, 5,403,340 and 6,328,925, each of which is
incorporated by reference herein in its entirety. The above lists
are intended for illustrative purposes only, and shall not be
construed as a limitation on the scope of the present
invention.
[0035] As best seen in FIG. 3, the inflatable balloon 30 can be
characterized as having an outer surface 34 and an opposed inner
surface 36 that surrounds an inflation volume 38 which can be
infused with a medical grade fluid to expand the inflatable balloon
30. More specifically, as shown in FIG. 1, an inflation device,
such as the syringe 40, can be used to pass a medical grade fluid
through the catheter tube 28 to expand the inflatable balloon
30.
[0036] Cross-referencing FIGS. 2 and 3, it can be seen that the
incising device 22 further includes a plurality of incising
elements which in this case are elongated atherotome blades 44. For
the catheter 20, the incising element is typically made of a
material which is harder than the targeted biological material
allowing the incising element to slice or break-apart the
biological material. These materials can include, but are not
limited to metals, ceramics, polymers such as hardened polymers,
composite materials and combinations thereof. For example, the
blade 44 can be made of a medical grade stainless steel.
[0037] For the embodiment shown, four longitudinally aligned blades
44 are uniformly distributed around the circumference of the
working section 32 of the inflatable balloon 30. Typically, each
blade 44 is made of a medical grade metal such as stainless steel.
As best seen in FIG. 3, a portion of each blade 44 is embedded in a
respective elastic folding member 46, thereby affixing the blade 44
to the respective folding member 46. From the folding member 46,
each blade 44 extends radially to a sharp cutting edge 48. For the
catheter 20, the blade 44 can be formed with a straight, uniform
cutting edge 48, as shown, and can be formed with notches,
serrations, or any other cutting edge feature known in the
pertinent art.
[0038] A better understanding of the folding member 46 can be
obtained with cross-reference to FIGS. 2-4. For the incising device
22, the folding member 46 is made of a flexible, elastic material,
such as one of the polymeric materials described above. Also, as
best seen in FIG. 4, each folding member 46 is formed with a wall
49 that is substantially shaped as an elongated tube when the
folding member 46 is in a relaxed (i.e. unstressed) state. The
tubular shaped folding member 46 defines a tube axis 50 in the
direction of elongation and is formed with an axially aligned slit
51 that extends radially through the wall 49. As further shown in
FIG. 4, the slit 51 establishes a pair of axially aligned edges 52,
54 that are substantially juxtaposed when the folding member 46 is
in the relaxed state. The tubular shaped folding member 46 also
defines a tube lumen 55, as shown.
[0039] Continuing with FIG. 4, the folding member 46 is bonded to
the outer surface 34 of the balloon 30 and oriented to align the
tube axis 50 substantially parallel to the balloon axis 33. With
this cooperation of structure, the folding member 46 covers and
protects the cutting edge 48 of the blade 44 when the balloon 30 is
deflated (and the folding member 46 is relaxed), as shown in FIG.
4. More specifically, as shown in FIG. 4, the folding member 46
extends radially beyond the cutting edge 48 of the blade 44 (which
is positioned in the lumen 55) to cover and protect the cutting
edge 48. For the embodiment shown in FIGS. 3 and 4, the blade 44 is
embedded in the folding member 46 at a location that is
substantially midway between the edges 52, 54.
[0040] As best seen in FIG. 3, when the balloon 30 is inflated, the
balloon 30 elastically deforms the folding member 46 to
substantially conform to the shape of the outer surface 34 of the
inflated balloon 30. Comparing FIG. 3 with FIG. 4, it can be seen
that the folding member 46 deforms from its initial tubular,
relaxed shape when the balloon 30 is in a deflated state (FIG. 4)
to a shape wherein the edges 52, 54 have separated from their
initial juxtaposed configuration when the balloon 30 is in an
inflated state (FIG. 3). It is to be appreciated that at some point
during a balloon inflation, the folding member 46 distends
sufficiently to expose the cutting edge 48 to thereby allow the
sharp cutting edge 48 to be driven into the target tissue. This can
be accomplished, for example, by further inflation of the balloon
30.
[0041] After the tissue has been incised by the cutting edge 48,
the balloon 30 can be deflated. With the balloon 30 deflated, the
folding member 46 returns to its relaxed shape as shown in FIG. 4.
During deflation of the balloon 30, the folding member 46 folds the
balloon 30 onto the catheter tube 28 (as shown in FIG. 4) to
facilitate removal of the incising device 22 from the patient 24
(see FIG. 1). Because the folding member 46 covers and protects the
cutting edge 48, inadvertent cutting of tissue is prevented and
balloon perforation is avoided during retrieval of the incising
device 22 from the treatment site.
[0042] FIG. 5 illustrates an alternate embodiment of an incising
device 122 in which a portion of the incising element (i.e.
atherotome blade 144) is embedded in the protective folding member
146 at a position that is closer to edge 152 of the folding member
146 than edge 154 of the folding member 146. As shown, the folding
member 146 is bonded to the outer surface 134 of the inflatable
balloon 130. FIG. 6 shows the folding member 146 in the relaxed
state, with the balloon 130 deflated and folded on the catheter
tube 128. As shown there, with the folding member 146 in the
relaxed state, the edge 154 is juxtaposed with edge 152 and the
edge 154 is positioned at a larger radial distance from the axis
133 than the edge 152. In some cases, the edge 154 can overlap with
the edge 152, as shown.
[0043] FIG. 7 illustrates another embodiment of an incising device
222 in which the incising element is an injector 256 for injecting
a medicament into selected tissue at a treatment site. The injector
256 is typically part of an injector strip which is aligned
longitudinally on the balloon 230 and includes a plurality of
injectors 256. The injector strip is placed in fluid communication
with a fluid pump (not shown) and fluid medicament source (not
shown), which can then be used to pump a medicament through each
injector 256 and into selected tissue. As shown, the injector 256
is mounted on a folding member 246 and extends therefrom to an
injector tip 258, which is typically sharp to allow the tip 258 to
incise tissue and embed a portion of the injector 256 in the
selected tissue. As shown, the folding member 246 is bonded to the
outer surface 234 of the balloon 230. FIG. 8 shows the tubular
folding member 246 in the relaxed state, with the balloon 230
deflated and folded. As shown there, with the folding member 246 in
the relaxed state, the tubular folding member 246 covers the sharp
injector tip 258 to prevent inadvertent cutting of tissue and
balloon perforation during retrieval of the incising device 222
from the treatment site.
[0044] In alternate embodiments of the catheter 20, the incising
element can have a shape other than a blade shape or injector. In
particular, any incising element that extends to an operative
surface feature capable of slicing or breaking apart biological
material can be used. For example, the incising element can be
formed as a round wire (not shown).
[0045] FIGS. 9 and 10 illustrate a refolding device 360 for an
angioplasty balloon 362. As shown, the refolding device 360
includes folding members 364a-c which are bonded to the outer
surface 366 of the angioplasty balloon 362. For the refolding
device 360, each folding member 364a-c is made of an elastic
material. FIG. 9 shows the folding members 364a-c in the relaxed,
tubular state, with the balloon 362 deflated and folded onto
catheter tube 368. As shown there, when the folding members 364a-c
are in the relaxed state, a respective first surface portion 370a-c
of each folding member 364a-c is convex and folds the angioplasty
balloon 362 into a respective pleat. Together, the folding members
364a-c fold the angioplasty balloon 362 onto the catheter tube 368
(as shown in FIG. 9) to facilitate removal of the angioplasty
balloon 362 from the patient. On the other hand, as shown in FIG.
10, when the angioplasty balloon 362 is inflated, the folding
member 364 elastically deforms to conform to the outer surface 366
of the inflated angioplasty balloon 362.
[0046] While the particular Elastically Distensible Folding Member
and corresponding methods of use as herein shown and disclosed in
detail are fully capable of providing the advantages herein before
stated, it is to be understood that they are merely illustrative of
the presently preferred embodiments of the invention and that no
limitations are intended to the details of construction or design
herein shown other than as described in the appended claims.
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